1. Technical Field
The present invention pertains to improvements in computerized simulation systems, typically of the type disclosed in U.S. patent application Ser. No. 08/401,507, filed Mar. 10, 1995, that corresponds to International Publication Number WO 96/28800, published Sep. 19, 1996, both of which are entitled "Computer Based Medical Procedure Simulation System", and the disclosures of which are incorporated herein by reference in their entireties. In particular, the present invention pertains to an interventional radiology interface device for a computerized medical procedure simulation system, the interface device including peripherals in the form of mock medical instruments for use by a physician in performing various steps of a medical procedure in order to provide an enhanced realistic simulation of that procedure.
2. Discussion of Related Art
Generally, minimally invasive surgical procedures, such as interventional radiological procedures, may be utilized by physicians to accomplish tasks that would otherwise require a patient to undergo open surgery. For example, an angioplasty-balloon procedure may be utilized by physicians to open and eliminate blockages in a blood vessel without subjecting a patient to open heart surgery. Briefly, in the actual angioplasty-balloon procedure, a variety of changeable guidewires, catheters and sheaths are inserted into a patient and manipulated through the patient's arterial network until reaching the point where a blockage occurs. The guidewire is disposed within the catheter which, in turn, is disposed within the sheath. Navigation of these components through the arterial network is aided by a fluoroscope display showing the positions of these radiopaque instruments within the arterial network. Upon reaching the blockage point, a contrasting fluid is injected into the patient, permitting the blockage to be viewed on the fluoroscope display. The catheter is changed to an angioplasty catheter with a balloon disposed at its distal end which is centered in the blockage region and inflated to compress the blockage material on the artery walls and open the blood passageway. Balloon inflation is viewed on the display to confirm that the balloon is appropriately inflated to eliminate the blockage without rupturing the artery walls.
Performance of minimally invasive surgical procedures, such as interventional radiological procedures, requires great skill to avoid complications that may cause serious injury to a patient and/or require the patient to undergo open surgery. For example, in an angioplasty-balloon procedure, the physician is required to navigate a guidewire, catheter and sheath through an arterial network to a blockage point and inflate a balloon to eliminate the blockage as described above while avoiding a number of possible complications, such as rupturing an artery wall or dissecting the wall of the artery. Thus, physicians need to acquire the necessary skill levels and experience to perform minimally invasive surgical procedures in order to ensure successful performance of these types of procedures on patients. Although practicing minimally invasive surgical procedures on live patients provides excellent training, a procedure may usually only be performed once on a particular live patient and typically requires the presence of a skilled physician to supervise and oversee the procedure to avoid serious injury to the patient. Further, training physicians or other medical professionals in minimally invasive surgical procedures on live patients requires the use of proper facilities and equipment (e.g., hospital facilities and equipment), thereby incurring substantial costs and limiting procedure practice to a particular time and location. Moreover, since only one physician is able to practice a procedure on a particular live patient, the quantity of physicians that may practice or perform minimally invasive surgical procedures is severely restricted, thereby limiting the quantity of physicians that may acquire sufficient experience to perform these types of procedures.
The prior art has attempted to overcome the above described disadvantages of utilizing live patients to train physicians or other medical professionals to perform various minimally invasive surgical procedures by employing simulation techniques. In particular, U.S. Pat. No. 4,907,973 (Hon) discloses an expert system simulator for modeling realistic internal environments. The simulator may be utilized to simulate an angioplasty-balloon operation wherein a mock catheter is inserted and manipulated within an internal arterial modeling device. The internal arterial modeling device may include mock arterial paths with sensors to track the progress of the inserted catheter within those paths. A computer retrieves and processes data from storage based on sensor data received from the internal sensors, and sends the processed data to a display that provides a visual display simulating a realistic environment (e.g., a view of the catheter within an arterial network).
U.S. Pat. No. 4,642,055 (Saliterman) discloses a hemodynamic monitoring training system that allows medical professionals to obtain substantial experience in hemodynamic monitoring (i.e., placement of a catheter passed from a distant vein through the heart to the pulmonary vasculature for purposes of measuring intracardiac, pulmonary artery and wedge pressures to determine the type or extent of cardiopulmonary disease, to evaluate therapeutic measures and to monitor cardiac function). The system includes a trainer, computer, display, keyboard and mouse and simulates the catheterization process. A catheter having a balloon disposed at its distal end is inserted within a trainer manikin at a catheter insertion point. The balloon is typically inflated to assist the catheter tip through the heart, and may be inflated in the pulmonary artery to measure wedge pressure. The manikin includes tubes representing veins extending internally from the insertion points, and a position sensor that measures advancement of the catheter tip past the sensor. The sensor data enables the computer to determine the location of the catheter tip within a corresponding actual human body based on catheter manipulation within the trainer manikin. The computer receives signals from the trainer and may provide on the display a simulated fluoroscope image showing simulated movement of the catheter through the heart and vasculature.
The Hon and Saliterman systems suffer from several disadvantages. Specifically, these systems utilize a physical model, thereby restricting training of a medical procedure to a particular bodily region or arterial paths defined by that model. Further, use of physical models degrades realism of the simulation and reduces the benefits of simulation training since the models usually do not contain substantially the same complex anatomy as an actual body, and permit a physician or other medical professional to become accustomed to performing a procedure on the same model anatomy. Performance of the procedure on another bodily region or through different arterial paths within the Hon and Saliterman systems typically requires a new model or substantial modifications to an existing model, thereby limiting flexibility of the systems and increasing system costs. Moreover, the Saliterman system does not provide computer-controlled force feedback to an instrument, thereby degrading realism of the simulation and reducing the benefits of simulation training. In other words, the Saliterman system does not provide a computer simulated feel of forces applied to an instrument during an actual medical procedure.
In order to overcome the disadvantages of utilizing physical models described above, medical procedure simulation systems employ virtual reality technology to simulate performance of a medical procedure on a virtual bodily region of interest. Various types of interface devices are typically utilized by these systems to enable a user to interact with the simulation system. In addition, the interface devices may provide force feedback to the user to simulate the forces encountered during an actual medical procedure. For example, International Publication Number WO 95/02233 (Jacobus et al) discloses a medical procedure simulation system that utilizes virtual reality technology and force feedback to provide an accurate simulation of endoscopic medical procedures. The system includes a display device, sound device, graphics/image processing engine and storage module and programmable tactile/force reflecting mechanisms (e.g., disposed within an interface device) that provide force feedback to generate the "feel" of medical instruments and the interaction of the instruments with an anatomical simulation. Force feedback is typically accomplished by a tactile/force reflecting mechanism via a four axis device that imparts forces and torques to a user's hands through a member representative of a medical instrument in response to manipulation of that member. The forces and torques are applied to the user's hands based on the position of the member in relation to characteristics of a geometric model of an organ or virtual reality simulation of a medical procedure environment. The forces and torques are typically generated by four servomotors that manipulate the member to provide a realistic feel during simulation.
U.S. Pat. No. 5,623,582 (Rosenberg) discloses a human/computer interface tool, typically for use with virtual reality simulation systems. The interface tool preferably interfaces a substantially cylindrical object, such as a shaft of a surgeon's tool, to a simulation system computer such that the computer may generate signals to provide a virtual reality simulation with force feedback applied to the object. The interface tool includes a gimbal mechanism having two degrees of freedom coupled to a support, and preferably three electromechanical transducers. The object, when engaged by the gimbal mechanism, may move with three degrees of freedom within a spherical coordinate space wherein each transducer is associated with and senses a respective degree of freedom of motion of the object. A fourth transducer may be utilized by the interface tool to measure rotation of the object about an axis. Alternatively, the interface tool may accommodate catheter insertion virtual reality systems, typically utilizing catheters having two degrees of freedom of motion, wherein the interface tool includes two transducers that are associated with and sense translation and rotation of a catheter, respectively. The transducers of the interface tool may include actuators to impart a force upon the object to provide force feedback to a user.
Another computer interface device for surgical simulation systems includes the Immersion PROBE produced by Immersion Corporation of Palo Alto, Calif. This interface device includes a pen-like stylus supported on a light-weight mechanical linkage having six degrees of freedom, and reports the position and orientation of the stylus to a computer via a serial port interface. Sensors are disposed at the linkage joints and send spatial coordinates (i.e., X, Y, Z) and orientation (i.e., roll, pitch, yaw) of the stylus to the computer.
The interface devices described above suffer from several disadvantages. In particular, the Jacobus system and tactile/force reflecting mechanisms are primarily directed toward simulation of endoscopic medical procedures and their associated instruments, and are typically not suited for accommodating medical procedures utilizing other types of instruments. Force feedback is accomplished within each Jacobus system tactile/force reflecting mechanism (e.g., disposed within an interface device) by a four axis device having several servomotors to generate the force feedback for only a single instrument, thereby increasing system complexity and cost. The Rosenberg interface tool typically may only accommodate a single instrument, thereby limiting the interface tool to simulation of only those medical procedure steps utilizing that instrument. Further, the Rosenberg interface tool typically may only accommodate an instrument having an elongated shaft, thereby limiting the interface tool to simulation of procedures or procedure steps that utilize a particular type of instrument compatible with the interface tool. Moreover, the Rosenberg interface tool includes a plurality of actuators to provide force feedback to only a single instrument, thereby increasing system complexity and cost. In addition, the Jacobus and Rosenberg interface devices described above each typically accommodate a limited quantity of instruments or a specific type of instrument for medical procedure simulation, thereby degrading realism of the simulation and reducing the benefits of simulation training since a physician or other medical professional may only gain experience for portions of a medical procedure utilizing particular instruments.
The interface device manufactured by Immersion Corporation does not resemble a common medical instrument and does not provide a manner to apply computer controlled force feedback to the interface device, thereby degrading realism of a simulation and reducing benefits of simulation training.
U.S. patent application Ser. No. 08/401,507 discloses a computer based medical simulation system including an interface device that attempts to overcome the disadvantages described above by enabling simulation of various aspects of a medical procedure. Specifically, the system simulates a variety of medical procedures, particularly catheter based procedures, such as an angioplasty-balloon procedure, and typically includes a catheter interface device that tracks a catheter wire and sends a signal to a computer to display movement of a virtual catheter within a virtual arterial network. A user manipulates the catheter wire during simulation of a medical procedure toward an occlusion in the arterial network wherein the computer generates signals to provide tactile feedback force to the catheter wire. The system may simulate other aspects of a medical procedure via a foot switch that is interfaced by the catheter interface device to enable simulation of injection of a drug, release of a contrast material for visualization of coronary arteries, and inflation of a virtual catheter balloon to remove the occlusion.
The system disclosed in U.S. patent application Ser. No. 08/401,507 may stand some improvement. Although this system simulates additional aspects of a medical procedure, such as drug injection, release of contrast material, and catheter balloon inflation, these aspects are enabled by a foot switch as opposed to the medical instruments normally utilized to perform these steps in an actual medical procedure. Thus, it is desirable to enhance realism of a simulated medical procedure and provide enhanced training of a medical procedure to physicians and other medical professionals by incorporating additional peripherals in the form of mock medical instruments into an interface device utilized by medical procedure simulation systems to enable realistic simulation of various aspects of a medical procedure.